Comprehensive and Detailed Explanation From Exact Extract:

Multi-column internal tables are defined using a structured row type, meaning each row is defined by a structure (either defined inline or as a global structure type in the Dictionary).

Option B is correct because it describes how internal tables with multiple fields are built using structured rows.

Option A is incorrect because the row type must be complete and consistent.

Option C is incorrect because nested components are not a requirement.

Option D is misleading. Though “complete data type” may sound correct, it lacks specificity. The correct technical description is that the row type is a structure.